These photos were all taken in forests in Slovenia. The country has over 580 mass graves from 1945-1946, when the communist party liquidated their opposition. Slovenia has loads of natural caves, so these were often used to dispose of bodies. The bones were in a hole in a forest floor, 30 meters deep and totally unmarked. Numbers in the graves range from a handful to tens of thousands, and only around one per cent have been excavated. It was illegal to visit the graves under communist rule, so people made crude markings on the trees to guide the relatives of victims. Last year and this year, a few of the graves received official markings.
I found the fox target in Tezno, at a shooting range built directly on top of an anti-tank trench filled with bodies. They excavated a portion, around a hundred meters, when building a motorway and found 1,179 remains. The trench is more than a kilometer long. Grobisce: Society, Politics, and Mass Graves just came out and is available here.